adding MIT License
Merge pull request #40 from phillip-haydon/License

- MIT License.
Update license.md
- BugFix: Google might not return a GenderType (can be null), so we now check that and set it to GenderType.Unknown.
- Added a helper method for converting some string to a GenderType (if possible).
- BugFix: An OpenId provider might not return a Gender. A check in place to handle this.
- Updated NuGet packages to prerelease v 0.19.0-Csrf-PewPew-4.
- Promoted WindowsLive to a 1st class citizen! Congrats Windows Live!
- WIP: Adding BitBucket provider.
- WIP: Trying more BitBucket stuff, to get it working.
- WIP: @ANurses' first commit, manually patched in.
- More of @ANurses code manually pulled in.
Preperation for merge into master.

- Removed BitBucket from the solution.
- Moved the GitHub and OpenId providers into their own namespaces.
- BugFix: One of the Csrf facts was failing. Now fixord.
Preparation for merge into master.

- Removed BitBucket from the solution.
- Moved the GitHub and OpenId providers into their own namespaces.
- Providers factshave their own folder/namespace.
- BugFix: One of the Csrf facts was failing. Now fixord.
WIP: Twitter isn't passing the state xsrf stuff across to Twitter. Time to check out what is going on ....
- GitHub now requests email address.
- OpenId works again with the Mvc controller.
- Mvc Controller RedirectToProvider(..) refactored to now accept an input model. (So there's room for future improvement).
- Twitter now passes the state across and back.
- Some better error messages in the AuthenticationService to help debug issues.
- BitBucket removed from master until we fix up how we handle Secret Tokens.
- Facebook picture now uses the Facebook Id instead of Username (which might be null).